busybox/editors/patch.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  *  busybox patch applet to handle the unified diff format.
   4  *  Copyright (C) 2003 Glenn McGrath <bug1@iinet.net.au>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  19  *
  20  *
  21  *
  22  *  This applet is written to work with patches generated by GNU diff,
  23  *  where there is equivalent functionality busybox patch shall behave
  24  *  as per GNU patch.
  25  *
  26  *  There is a SUSv3 specification for patch, however it looks to be
  27  *  incomplete, it doesnt even mention unified diff format.
  28  *  http://www.opengroup.org/onlinepubs/007904975/utilities/patch.html
  29  *
  30  *  Issues
  31  *   - Non-interactive
  32  *   - Patches must apply cleanly or the hunk will fail.
  33  *   - Reject file isnt saved
  34  *   -
  35  */
  36
  37 #include <getopt.h>
  38 #include <string.h>
  39 #include <stdlib.h>
  40 #include <unistd.h>
  41 #include "busybox.h"
  42 #include "libbb.h"
  43
  44 static int copy_lines(FILE *src_stream, FILE *dest_stream, const unsigned int lines_count)
  45 {
  46         int i = 0;
  47
  48         while (src_stream && (i < lines_count)) {
  49                 char *line;
  50                 line = bb_get_line_from_file(src_stream);
  51                 if (line == NULL) {
  52                         break;
  53                 }
  54                 if (fputs(line, dest_stream) == EOF) {
  55                         bb_perror_msg_and_die("Error writing to new file");
  56                 }
  57                 free(line);
  58
  59                 i++;
  60         }
  61         return(i);
  62 }
  63
  64 /* If patch_level is -1 it will remove all directory names
  65  * char *line must be greater than 4 chars
  66  * returns NULL if the file doesnt exist or error
  67  * returns malloc'ed filename
  68  */
  69
  70 static unsigned char *extract_filename(char *line, unsigned short patch_level)
  71 {
  72         char *filename_start_ptr = line + 4;
  73         int i;
  74
  75         /* Terminate string at end of source filename */
  76         {
  77                 char *line_ptr;
  78                 line_ptr = strchr(filename_start_ptr, '\t');
  79                 if (!line_ptr) {
  80                         bb_perror_msg("Malformed line %s", line);
  81                         return(NULL);
  82                 }
  83                 *line_ptr = '\0';
  84         }
  85
  86         /* Skip over (patch_level) number of leading directories */
  87         for (i = 0; i < patch_level; i++) {
  88                 char *dirname_ptr;
  89
  90                 dirname_ptr = strchr(filename_start_ptr, '/');
  91                 if (!dirname_ptr) {
  92                         break;
  93                 }
  94                 filename_start_ptr = dirname_ptr + 1;
  95         }
  96
  97         return(bb_xstrdup(filename_start_ptr));
  98 }
  99
 100 static int file_doesnt_exist(const char *filename)
 101 {
 102         struct stat statbuf;
 103         return(stat(filename, &statbuf));
 104 }
 105
 106 extern int patch_main(int argc, char **argv)
 107 {
 108         unsigned int patch_level = -1;
 109         char *patch_line;
 110         int ret = 0;
 111
 112         /* Handle 'p' option */
 113         if (argv[1] && (argv[1][0] == '-') && (argv[1][1] == 'p')) {
 114                 patch_level = atoi(&argv[1][2]);
 115         }
 116
 117         patch_line = bb_get_line_from_file(stdin);
 118         while (patch_line) {
 119                 FILE *src_stream;
 120                 FILE *dst_stream;
 121                 char *original_filename;
 122                 char *new_filename;
 123                 char *backup_filename;
 124                 unsigned int src_cur_line = 1;
 125                 unsigned int dest_cur_line = 0;
 126                 unsigned int dest_beg_line;
 127                 unsigned int bad_hunk_count = 0;
 128                 unsigned int hunk_count = 0;
 129                 char copy_trailing_lines_flag = 0;
 130
 131                 /* Skip everything upto the "---" marker
 132                  * No need to parse the lines "Only in <dir>", and "diff <args>"
 133                  */
 134                 while (patch_line && strncmp(patch_line, "--- ", 4) != 0) {
 135                         free(patch_line);
 136                         patch_line = bb_get_line_from_file(stdin);
 137                 }
 138
 139                 /* Extract the filename used before the patch was generated */
 140                 original_filename = extract_filename(patch_line, patch_level);
 141                 free(patch_line);
 142
 143                 patch_line = bb_get_line_from_file(stdin);
 144                 if (strncmp(patch_line, "+++ ", 4) != 0) {
 145                         ret = 2;
 146                         bb_error_msg("Invalid patch");
 147                         continue;
 148                 }
 149                 new_filename = extract_filename(patch_line, patch_level);
 150                 free(patch_line);
 151
 152                 if (file_doesnt_exist(new_filename)) {
 153                         char *line_ptr;
 154                         /* Create leading directories */
 155                         line_ptr = strrchr(new_filename, '/');
 156                         if (line_ptr) {
 157                                 *line_ptr = '\0';
 158                                 bb_make_directory(new_filename, -1, FILEUTILS_RECUR);
 159                                 *line_ptr = '/';
 160                         }
 161                         dst_stream = bb_xfopen(new_filename, "w+");
 162                         backup_filename = NULL;
 163                 } else {
 164                         backup_filename = xmalloc(strlen(new_filename) + 6);
 165                         strcpy(backup_filename, new_filename);
 166                         strcat(backup_filename, ".orig");
 167                         if (rename(new_filename, backup_filename) == -1) {
 168                                 bb_perror_msg_and_die("Couldnt create file %s", backup_filename);
 169                         }
 170                         dst_stream = bb_xfopen(new_filename, "w");
 171                 }
 172
 173                 if ((backup_filename == NULL) || file_doesnt_exist(original_filename)) {
 174                         src_stream = NULL;
 175                 } else {
 176                         if (strcmp(original_filename, new_filename) == 0) {
 177                                 src_stream = bb_xfopen(backup_filename, "r");
 178                         } else {
 179                                 src_stream = bb_xfopen(original_filename, "r");
 180                         }
 181                 }
 182
 183                 printf("patching file %s\n", new_filename);
 184
 185                 /* Handle each hunk */
 186                 patch_line = bb_get_line_from_file(stdin);
 187                 while (patch_line) {
 188                         unsigned int count;
 189                         unsigned int src_beg_line;
 190                         unsigned int unused;
 191                         unsigned int hunk_offset_start = 0;
 192                         int hunk_error = 0;
 193
 194                         /* This bit should be improved */
 195                         if ((sscanf(patch_line, "@@ -%d,%d +%d,%d @@", &src_beg_line, &unused, &dest_beg_line, &unused) != 4) &&
 196                                 (sscanf(patch_line, "@@ -%d,%d +%d @@", &src_beg_line, &unused, &dest_beg_line) != 3) &&
 197                                 (sscanf(patch_line, "@@ -%d +%d,%d @@", &src_beg_line, &dest_beg_line, &unused) != 3)) {
 198                                 /* No more hunks for this file */
 199                                 break;
 200                         }
 201                         free(patch_line);
 202                         hunk_count++;
 203
 204                         if (src_beg_line && dest_beg_line) {
 205                                 /* Copy unmodified lines upto start of hunk */
 206                                 /* src_beg_line will be 0 if its a new file */
 207                                 count = src_beg_line - src_cur_line;
 208                                 if (copy_lines(src_stream, dst_stream, count) != count) {
 209                                         bb_error_msg_and_die("Bad src file");
 210                                 }
 211                                 src_cur_line += count;
 212                                 dest_cur_line += count;
 213                                 copy_trailing_lines_flag = 1;
 214                         }
 215                         hunk_offset_start = src_cur_line;
 216
 217                         while ((patch_line = bb_get_line_from_file(stdin)) != NULL) {
 218                                 if ((*patch_line == '-') || (*patch_line == ' ')) {
 219                                         char *src_line = NULL;
 220                                         if (src_stream) {
 221                                                 src_line = bb_get_line_from_file(src_stream);
 222                                                 if (!src_line) {
 223                                                         hunk_error++;
 224                                                         break;
 225                                                 } else {
 226                                                         src_cur_line++;
 227                                                 }
 228                                                 if (strcmp(src_line, patch_line + 1) != 0) {
 229                                                         bb_error_msg("Hunk #%d FAILED at %d.", hunk_count, hunk_offset_start);
 230                                                         hunk_error++;
 231                                                         free(patch_line);
 232                                                         break;
 233                                                 }
 234                                                 free(src_line);
 235                                         }
 236                                         if (*patch_line == ' ') {
 237                                                 fputs(patch_line + 1, dst_stream);
 238                                                 dest_cur_line++;
 239                                         }
 240                                 } else if (*patch_line == '+') {
 241                                         fputs(patch_line + 1, dst_stream);
 242                                         dest_cur_line++;
 243                                 } else {
 244                                         break;
 245                                 }
 246                                 free(patch_line);
 247                         }
 248                         if (hunk_error) {
 249                                 bad_hunk_count++;
 250                         }
 251                 }
 252
 253                 /* Cleanup last patched file */
 254                 if (copy_trailing_lines_flag) {
 255                         copy_lines(src_stream, dst_stream, -1);
 256                 }
 257                 if (src_stream) {
 258                         fclose(src_stream);
 259                 }
 260                 if (dst_stream) {
 261                         fclose(dst_stream);
 262                 }
 263                 if (bad_hunk_count) {
 264                         if (!ret) {
 265                                 ret = 1;
 266                         }
 267                         bb_error_msg("%d out of %d hunk FAILED", bad_hunk_count, hunk_count);
 268                 } else {
 269                         /* It worked, we can remove the backup */
 270                         if (backup_filename) {
 271                                 unlink(backup_filename);
 272                         }
 273                         if ((dest_cur_line == 0) || (dest_beg_line == 0)) {
 274                                 /* The new patched file is empty, remove it */
 275                                 if (unlink(new_filename) == -1) {
 276                                         bb_perror_msg_and_die("Couldnt remove file %s", new_filename);
 277                                 }
 278                                 if (unlink(original_filename) == -1) {
 279                                         bb_perror_msg_and_die("Couldnt remove original file %s", new_filename);
 280                                 }
 281                         }
 282                 }
 283         }
 284
 285         /* 0 = SUCCESS
 286          * 1 = Some hunks failed
 287          * 2 = More serious problems
 288          */
 289         return(ret);
 290 }